Question 1

Glucose is to starch as ________

Accepted Answer

A) pure gold is to 14-karat gold. 
B) a link is to a chain. 
C) a leaf is to a tree. 
D) a trumpet is to a tuba. 
E) a tomato is to a potato. 
A) pure gold is to 14-karat gold. 
B) a link is to a chain. 
C) a leaf is to a tree. 
D) a trumpet is to a tuba. 
E) a tomato is to a potato.

Question 2

How many chiral centers are there in the following molecule?

Accepted Answer

A) 0 
B) 1 
C) 2 
D) 3 
E) 4 
A) 0 
B) 1 
C) 2 
D) 3 
E) 4

Question 3

Which of the noted functional group(s) is/are found in the following molecule?

Accepted Answer

A) only a carboxylic acid 
B) only an ester 
C) only an ether 
D) only a ketone 
E) both an ether and a ketone 
A) only a carboxylic acid 
B) only an ester 
C) only an ether 
D) only a ketone 
E) both an ether and a ketone

Question 4

How many structural isomers (also called constitutional isomers) are there for butene, and why?

Accepted Answer

A) two, because of resonance 
B) two, because of geometrical isomerism and two of the structures can be superimposed 
C) two, because the double bond can be in either one of two locations 
D) three, because of geometrical isomerism and the double bond can be in different locations 
E) three, because of resonance and the double bond can be in different locations 
A) two, because of resonance 
B) two, because of geometrical isomerism and two of the structures can be superimposed 
C) two, because the double bond can be in either one of two locations 
D) three, because of geometrical isomerism and the double bond can be in different locations 
E) three, because of resonance and the double bond can be in different locations

Question 5

Which statement about amino acid enantiomers is not correct?

Accepted Answer

A) An enantiomer cannot be superimposed on its mirror image. 
B) Enantiomers are examples of stereoisomers. 
C) A solution of an enantiomer rotates the plane of polarized light. 
D) Enantiomers are designated by the prefixes D and L. 
E) All the chiral amino acids in our bodies are mixtures of enantiomers. 
A) An enantiomer cannot be superimposed on its mirror image. 
B) Enantiomers are examples of stereoisomers. 
C) A solution of an enantiomer rotates the plane of polarized light. 
D) Enantiomers are designated by the prefixes D and L. 
E) All the chiral amino acids in our bodies are mixtures of enantiomers.

Question 6

At a physiological pH of 7.4, amino acids exist as zwitterions. At a very low pH (in an acid solution), both the amine group and the carboxylic acid group on an amino acid are protonated. Therefore, the following must be true: the pKa of the ________ group is larger than the pKa of the ________ group.

Accepted Answer

A) protonated amine; carboxylic acid 
B) carboxylic acid; protonated amine 
C) amine; carbonate 
D) hydronium ion; hydroxyl ion 
E) carbonate; amine 
A) protonated amine; carboxylic acid 
B) carboxylic acid; protonated amine 
C) amine; carbonate 
D) hydronium ion; hydroxyl ion 
E) carbonate; amine

Question 7

Which one of the following is not an amino acid?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 8

What is the substrate in the context of an enzyme-catalyzed reaction?

Accepted Answer

The substrate is the

Question 9

Which one of the following statements about biomolecules is not correct?

Accepted Answer

A) Table sugar (sucrose) is a disaccharide made of glucose and fructose. 
B) Starch and cellulose are polysaccharides made from glucose. 
C) A glycosidic linkage in polysaccharides is an ether group. 
D) Cellobiose is a disaccharide composed of two glucose monomers. 
E) Maltose is a disaccharide composed of two fructose monomers. 
A) Table sugar (sucrose) is a disaccharide made of glucose and fructose. 
B) Starch and cellulose are polysaccharides made from glucose. 
C) A glycosidic linkage in polysaccharides is an ether group. 
D) Cellobiose is a disaccharide composed of two glucose monomers. 
E) Maltose is a disaccharide composed of two fructose monomers.

Question 10

An ether linkage connects monomers in ________

Accepted Answer

A) proteins. 
B) nucleic acids. 
C) carbohydrates. 
D) lipids. 
E) steroids. 
A) proteins. 
B) nucleic acids. 
C) carbohydrates. 
D) lipids. 
E) steroids.

Question 11

Two dipeptides can be produced from the amino acids glycine and alanine. Draw their structures and label the structures with the names of these peptides. The R groups are H for glycine and CH3 for alanine.

Accepted Answer

Note: The N terminus

Question 12

The molecule drawn below is an example of ________

Accepted Answer

A) a nucleic acid base. 
B) an amino acid. 
C) a carbohydrate. 
D) a fatty acid. 
E) a lipid. 
A) a nucleic acid base. 
B) an amino acid. 
C) a carbohydrate. 
D) a fatty acid. 
E) a lipid.

Question 13

Which one of the following is best associated with nucleic acids?

Accepted Answer

A) amino acids 
B) saccharides 
C) hydrocarbon chains 
D) phosphate linkages 
E) hydrocarbon rings 
A) amino acids 
B) saccharides 
C) hydrocarbon chains 
D) phosphate linkages 
E) hydrocarbon rings

Question 14

In DNA, the base guanine can pair with ________

Accepted Answer

A) thymine. 
B) uracil. 
C) cytosine. 
D) adenine. 
E) guanine. 
A) thymine. 
B) uracil. 
C) cytosine. 
D) adenine. 
E) guanine.

Question 15

Which of the following molecular formulas identifies a monosaccharide?

Accepted Answer

A) CH2O 
B) C6H10O5 
C) C12H22O11 
D) C2H4O2 
E) C6H12O6 
A) CH2O 
B) C6H10O5 
C) C12H22O11 
D) C2H4O2 
E) C6H12O6

Question 16

Which one of the following is an example of a monosaccharide?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 17

Draw all of the isomers for butanol. Include structural isomers and stereoisomers, both geometric and optical.

Accepted Answer

The answer of Draw all of the isomers for butanol....

Question 18

The cyclization of fructose forms a ________

Accepted Answer

A) four-membered ring. 
B) five-membered ring. 
C) six-membered ring. 
D) seven-membered ring. 
E) double ring. 
A) four-membered ring. 
B) five-membered ring. 
C) six-membered ring. 
D) seven-membered ring. 
E) double ring.

Question 19

Which of the following statements is not true about enzyme catalysis?

Accepted Answer

A) The reactant in an enzymatic reaction is called a substrate. 
B) The lock-and-key model of enzyme catalysis relies on a perfect fit between enzyme and reactant to promote reaction. 
C) The active site is the region of the protein that binds the reactant. 
D) Inhibitors can bind only at the enzyme-active site to prevent reaction from occurring. 
E) The induced fit model assumes that subtle changes mediated by reactant binding in the enzyme-active site lower the barrier for the desired reaction. 
A) The reactant in an enzymatic reaction is called a substrate. 
B) The lock-and-key model of enzyme catalysis relies on a perfect fit between enzyme and reactant to promote reaction. 
C) The active site is the region of the protein that binds the reactant. 
D) Inhibitors can bind only at the enzyme-active site to prevent reaction from occurring. 
E) The induced fit model assumes that subtle changes mediated by reactant binding in the enzyme-active site lower the barrier for the desired reaction.

Question 20

Which of the following is the correct structure of alanine at its isoelectric point?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Exam 20: Organic and Biological Molecules: the Compounds of Life

Glucose is to starch as ________

How many chiral centers are there in the following molecule?

Which of the noted functional group(s) is/are found in the following molecule?

How many structural isomers (also called constitutional isomers) are there for butene, and why?

Which statement about amino acid enantiomers is not correct?

Which one of the following is not an amino acid?

What is the substrate in the context of an enzyme-catalyzed reaction?

Which one of the following statements about biomolecules is not correct?

An ether linkage connects monomers in ________

Two dipeptides can be produced from the amino acids glycine and alanine. Draw their structures and label the structures with the names of these peptides. The R groups are H for glycine and CH3 for alanine.

The molecule drawn below is an example of ________

Which one of the following is best associated with nucleic acids?

In DNA, the base guanine can pair with ________

Which of the following molecular formulas identifies a monosaccharide?

Which one of the following is an example of a monosaccharide?

Draw all of the isomers for butanol. Include structural isomers and stereoisomers, both geometric and optical.

The cyclization of fructose forms a ________

Which of the following statements is not true about enzyme catalysis?

Which of the following is the correct structure of alanine at its isoelectric point?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

Two dipeptides can be produced from the amino acids glycine and alanine. Draw their structures and label the structures with the names of these peptides. The R groups are H for glycine and CH₃ for alanine.